An Optical True Time Delay Transmitting Array for Terahertz Broadband Communications

This paper addresses the issues of efficient transmission, radiation and high-precision delay calibration of terahertz (THz) optical true time delay (OTTD) antenna arrays. To this end, we propose an effective medium-clad antenna aperture and a delay calibration method based on the amplitude-frequency response. The resulting broadband THz OTTD transmitting array is presented as a solution to the aforementioned problems. The transmitting array comprises a 4-element dielectric rod antenna based on an effective medium clad transmission line, exhibiting high transmission and radiation efficiency. Furthermore, a calibration method based on the amplitude-frequency characteristics of the radiated electric field is proposed, which enables full-link calibration from the input optical signals to the output THz signals. This calibration method is characterized by high resolution and low complexity. We processed the antenna aperture and the OTTD transmitting array. The measured results show that this transmitting array is capable of realizing a beam scanning range of ±35° in the frequency range from 110–145 GHz. Meanwhile, we modulated 8 Gbps on-off keying (OOK) signals on the transmitting array, and the measurement results show that the proposed transmitting array is capable of realizing high-quality communication signal transmission with 0° and 20° beam deflection. The transmitting array proposed in this paper exhibits instantaneous wideband and wide-angle scanning performance, making it highly valuable for applications in the THz communication field.